Specifies the display screen on which
the Xv Server is to accept requests from Xv clients. If the display option
is not specified, Xv uses the display screen specified by your DISPLAY
environment variable. The display option has the format hostname:number.
Using two colons (::) instead of one (:) indicates that DECnet is to be
used for transport.

port

Defines the port from which to get the still.

d

Defines
the drawable into which the still is to be written. Pixmaps are currently
not supported.

Define the location
and size of the video region to be written. vx and vy define the upper-left
pixel of the region. vw and vh define the width and height, in pixels, of
the region.

dx,dy,dw,dh

Define the location and size of the destination region
into which the still image is written. dx and dy define the upper-left
corner of the region. dw and dh define the width and height, in pixels,
of the region.

Video data is clipped
to the bounds of the video encoding, scaled to the requested drawable region
size (or the closest size supported) and clipped to the bounds of the drawable.

If the port is grabbed by another client, this request is ignored, and
an XvVideoNotify event with detail XvBusy is generated for the drawable.
If the port is not receiving a valid video signal a VideoNotify event
with detail XvHardError is generated for the drawable.